Crystalline ferrosilicon product and method of making the same.



H. c. HARRISON. CRYSTALLINE FERROSILICON PRODUCT AND METHOD OF MAKINGTHE SAME.

APPLICATION FILED JULY30, I909- RENEWED SEPT. I, 1914.

1, 1 34,1 Q7 Patented Apr. 6, 191:5.

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HERBERT CHAMPION HARRISON, OF LOCKPORT, NEW YORK, ASSIGNOR, BY MESNEASSIGNMENTS, TO ELECTRO METALLURGICAL COMPANY, A CORPORATION OF WESTVIRGINIA;

CRYSTALIIINE FERROSILICON PRODUCT AND METHOD OF MAKING THE SAME.

Application filed July 30, 1909, Serial No. 510,477.

To all whom it may concern:

Be it known that I, HERBERT CHAMPION HARRISON, a subjectof the King ofGreat Britain, residing at Lockport, in the county of Niagara and Stateof New York, have invented certain new and useful Improvements inCrystalline Ferrosilicon Products and Methods of Making the Same; and Ido hereby declare the following tobe a full, clear, and exactdescription of the invention, such as will enable others skilled in theart to which it appertains to make and use the same.

This invention relates to crystalline ferrosilicon products and methodsof producing the same, and has for its object to produce such a productin a crystalline form which will correspond substantially to the formulaFe Si,, or to 54.2 per cent. silicon.

With these objects in view the invention consists in the novel methodand product hereinafter more fully disclosed and particularly pointedout in the claims.

Referring to the drawing forming a part of this specification, in whichthe figure illustrates a conventional form of an electric furnacesuitable for carrying out the process, and for producing the product: 1represents suitable electrodes, 2 the furnace, 3 the charge, and 4 themolten product.

In carrying out the method, the ferrosilicon charge is so proportionedthat there will be produced a ferro-silicon alloy containing as nearlyas possible between 53 and 54.5 per cent. of silicon. The same is heatedin the furnace in the usual way, is tapped out and cooled and thenbroken up, when throughout the product are found matrices filled withbright, shining, hard, brittle crystals in a plate form which analyzeabout 54.2 per cent. silicon, depending upon whether the particularmatrix selected is relatively rich or poor in silicon. If the matrices.are melted and permitted to cool, these crystals invariably solidifyfirst, which tends to show that they have a higher melting point thanthe ferro-silicon alloys on either side of the same. Crystals from thepoorer matrices probably contain about .7 per cent. of impurities, whilecrystals from rich matrices analyze practically 54.2 per cent. silicon,corresponding to the formula Fe st taking the atomic weight of iron as55.9, and of silicon as 28.4. These crystals are, of course, a

Specification of Letters Patent.

Patented Apr. 6, 1915.

Renewed September 1, 1914. Serial No. 859,721.

much purer compound of iron and silicon than the usual commercialalloys, and, therefore, they offer special advantages in metallurgy,over the regular alloys of say, 25 to 60 per cent. silicon. They containless carbonand phosphorous than do such alloys, and hav ng a slightlyhigher melting point than the 1mpurer alloys they are less likely tolose their s1l1con during the process of purifying the metal. In otherwords, it is well recognlzed 1n metallurgy, that it is very important toobtain the purest product possible, and it is obvlous that a crystallineproduct of this nature 1s purer than the'chance alloys here toforeemployed. It is also probable that when the silicon is liberated from achemical compound, as is the case here, it being. in'a nascent state, soto speak, that it will be more active chemically in the molten iron thanwould be the case were it merely liberated from an alloy.

In many cases the crystals need not be separated from their matricesbefore being used, for the mixture consisting of the crystals andmatrices can always be depended on to analyze substantially between 53and 54.5 per cent. of silicon, which is a product sufiiciently pure formany purposes. If the charge is made up so as to produce other than 53to 54.5 per cent. of silicon the crystal product becomes less, and itcan be made to so widely differ from this silicon content that, thecrystal product will disappear entlrely. In some cases the matrices oneither side of the crystals are found to contain only about 51.28% ofsilicon.

What I claim is:

1. The method of producing crystalline IEBI'IO S1l1CO I1 correspondingto the formula Fe s WhICh consists in so chemically proportiomng aferro-silicon furnace charge as to produce substantially between 53 and54.5 per cent. of silicon; and in suitably producing ferro silicon fromsaid charge in an electric furnace by maintaining the temperature at orabove a predetermined critical temperature, substantially as described.

2. The method of producing crystalline ferro-silicon corresponding tothe formula 'I e,Si,, which consists in "so chemically proportioning aferro-silicon furnace charge as to produce substantially between 53 and54.5 per cent. of silicon; in suitably producing ferro-silicon from saidcharge in an electric furnace by maintaining a constant temperatureabove a critical temperature; and in separating out the crystals thusformed, sub stantially as described.

3. The herein described ferro-silicon product consisting of matrices offerro-silicon containing substantially between 53 and 54.5 per cent. ofsilicon and charged with ferrosilicon crystals corresponding to theformula 10 Fe Si substantially as escribed.

' 4. The hereindescribed ferro-silicon product consisting of bright,hard, brittle, plate like, crsytals corresponding to the formula Fe Si,;substantially as described.

In testimony whereof, I aflix my signature, in presence of twoWitnesses.

HERBERT CHAMPION HARRISON. Witnesses:

W. R. CULMER, N. GOULD ALIEN

